Contact means for electrical switches



Sept. 30, 1969 T. A. RILEY CONTACT MEANS FOR ELECTRICAL SWITCHES 3 Sheets-Sheet l I Filed Oct. 10, 1967 FIG.3

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IN VE N TOR TEKENCE flLEXA/VDEK K/LEV P 30, 1959 r. A. RILEY 3,470,501

CONTACT MEANS FOR ELECTRICAL SWITCHES Filed Oct. 10, 1967 3 Sheets-Sheet 2:

m VENI'OK TEKENcc ALEXANAEK RILEY CONTACT MEANS FOR ELECTRICAL SWITCHES Filed on. 10, 1967 3 Sheets-Sheefi' INVENTOK TE EAKE ALLXANPER KIM) Min A TTOE/VE Y8 United States Patent 3,470,501 CONTACT MEANS FOR ELECTRICAL SWITCHES Terence Alexander Riley, Camberley, England, assignor to Inertia Switch Limited, Camberley, Surrey, England, a British company Filed Oct. 10-, 1967, Ser. No. 674,354 Claims priority, application Great Britain, Oct. 10, 1966, 45,136 66 Int. Cl. H01h N16 US. Cl. 335-1 7 Claims ABSTRACT OF THE DISCLOSURE An electrical switch having a contact element in the form of a conductive sphere or cylinder rollable along a pair of wires forming a track. A further wire is disposed adjacent the track and is adapted to be contacted by the rollable contact element at a selected position. A magnet may be provided for urging the rollable contact element into a normal operating position.

The invention relates to means for making electrical contact in switches or the like.

Switches using a ball as a current carrying circuit make and break element are known. A ball contactor normally requires three points of contact for stability, and, when the ball rests against plane surfaces, the three points are usually poorly defined high spots in the surfaces. One solution has been to have a contactor formed by a ball running in a machine produced tubular sleeve which was internally plated with a noble metal to improve the contact quality.

The invention has among its object to improve the contact means of electric switches containing a rollable member as a movable element.

According to the invention contact means in an electric switch comprise a rollable contact member, for example a sphere or cylinder, of electrically conductive material, or having an electrically conductive surface, a pair of-wires disposed to form a track along which the contact member is rollable and at least one further wire disposed to contact the said member at one position within its movement on the pair of wires.

The pair of wires, preferably parallel, thus support the contact member which is advantageously biased in favour of one position on said pair of wires such as at one end of the wires, by restraining means, for example by a magnet cooperating with a magnetic contact member, and when freed rolls along the pair of wires to contact the further wire, which is advantageously at right angles to the pair of wires, thereby completing an electrical circuit. The switch can be arranged to break a circuit instead of making one.

The invention is diagrammatically illustrated by way of example in the accompanying drawings in which:

FIGURES 1 and 2 are respectively an end view and plan view of a ball and contact wires according to the invention;

FIGURES 3 and 4 are respectively an end view and plan view of an alternative embodiment;

FIGURE 5 is an end view of a switch having contact means according to the invention;

FIGURE 6 is a sectional view on line AA of FIG- URE 5;

FIGURE 7 is a sectional view on line B-B of FIG- URE 6, and

FIGURE 8 shows side and end views of an embodiment using a cylindrical contact member.

As shown in FIGURES 1 to 4, a ball 1 is mounted on a pair of parallel wires 2 and is disposed at one end ice of the wires, to contact a third wire, which in FIGURES l and 2 is a horizontally extending wire 3 and in FIG- URES 3 and 4 is a vertically extending wire 4. The wires 2 thus form a track for a ball to travel along.

As shown in FIGURES 5 to 7 a switch comprises a housing 5 having a securing flange 6 and a body portion 7 with a bore therein into which an insert 8 may be pressed.

The insert 8 bears a U-shaped member 9 of conductive material upon which a ball 10 rests in electrical contact with the member 9. The ball 10* in the position shown in the drawings, is also in contact with the cross-piece of a further U-shaped member 11, also secured in the member 8 and of electrically conductive material. A magnet 12 in the member 8 holds the ball 10 in the position shown until impact or vibration shakes it loose therefrom to break the contact between the ball and the U shaped member 11. The members 9 and 11 are extended through the member 8 to form external connection members 9a and 11a respectively for an indication circuit.

The switch can thus simply be made of parts which need not be precision made, the parts 5 and 8 advantageously being plastics mouldings.

As shown in FIGURE 8, the rollable contact member may comprise a cylinder 13 having end portions of reduced diameter for rolling along a pair of parallel wires 2. Further wires 3, which may be either horizontal or vertical, are disposed to intercept the contact member at either extremity of its travel. A magnet may be provided at either or both ends of the track formed by the pair of parallel wires, or in an intermediate position.

I claim:

1. An electrical switch, comprising:

a guide track including a first elongated electrically conductive wire and an elongated wire-like member spaced from and extending in substantially the same direction as said first wire;

a second eltctrically conductive wire spaced from both said first wire and said wire-like member, said second wire having a portion extending in a direction which is at an angle relative to the elongated direction of both said first wire and said wire-like member; and

contact means for creating an electrical circuit between said first and second wires, said contact means including a rollable contact element of which at least the surface is electrically conductive, the rollable contact element being rollingly supported on and in contact with said first wire and said wire-like member and being movable thereon between (1) a first position wherein said element contacts said first wire and said portion of said second wire to create an electrically conductive circuit and (2) a second position wherein said contact element is out of contact with said second wire to interrupt the electrical circuit between said first and second wires.

2. An electrical switch according to claim 1, wherein the rollable contact element comprises a sphere.

3. An electrical switch according to claim 1, wherein the rollable contact element comprises a cylindrical member having a central cylindrical portion and opposite end cylindrical portions of smaller diameter than said central cylindrical portions, said central cylindrical portion being positioned between said first wire and said wirelike member with said end cylindrical portions being in rolling engagement with said first wire and said wire-like member.

4. An electrical switch according to claim 1, wherein said first wire and said wire-like member are integrally interconnected and comprise the legs of a U-shaped electrically conductive track member.

5. An electrical switch according to claim 1, further including magnetic means cooperating with said contact element for normally maintaining same in one of said first and second positions.

6. An electrical switch according to claim 1, wherein said portion of said second wire is substantially parallel to and laterally spaced from a plane defined by the longitudinal axes of said first wire and said wire-like member, said portion extending between said first wire and said wire-like member in a direction substantially transverse to the elongated direction of said first wire.

7. An electrical switch according to claim 1, wherein said portion of said second wire is positioned between and laterally spaced from said first wire and said wire-like tially transverse to a plane defined by the longitudinal axes of said first wire and said wire-like member.

References Cited UNITED STATES PATENTS 2,997,557 8/1961 Gillmor 200-4153 3,108,252 10/1963 Torres ....1 20061.53 3,295,101 12/ 1966 Ellis 200-45145 10 BERNARD A. GILHEANY, Primary Examiner H. BROOME, Assistant Examiner US. Cl. X.R.

member, said portion extending in a direction substan- 15 200-6153 

